9,234 research outputs found
The water cycle in a changing climate
Millions of people across the globe are already affected by natural variability in the water cycle. A multidisciplinary team of experts from the University of East Anglia and the University of Nottingham, led by Timothy Osborn, Professor of Climate Science at the world-renowned Climatic Research Unit, set out the empirical evidence - and argue the need for implementation of measured adaptation mechanisms that take into account uncertainties in the projection of future precipitation patterns
Loss Dependence on Geometry and Applied Power in Superconducting Coplanar Resonators
The loss in superconducting microwave resonators at low-photon number and low
temperatures is not well understood but has implications for achievable
coherence times in superconducting qubits. We have fabricated single-layer
resonators with a high quality factor by patterning a superconducting aluminum
film on a sapphire substrate. Four resonator geometries were studied with
resonant frequencies ranging from 5 to 7 GHz: a quasi-lumped element resonator,
a coplanar strip waveguide resonator, and two hybrid designs that contain both
a coplanar strip and a quasi-lumped element. Transmitted power measurements
were taken at 30 mK as a function of frequency and probe power. We find that
the resonator loss, expressed as the inverse of the internal quality factor,
decreases slowly over four decades of photon number in a manner not merely
explained by loss from a conventional uniform spatial distribution of two-level
systems in an oxide layer on the superconducting surfaces of the resonator.Comment: 4 pages, 5 figures, Submitted to ASC 2010 conference proceeding
Optical Production of Stable Ultracold Sr Molecules
We have produced large samples of ultracold Sr molecules in the
electronic ground state in an optical lattice. The molecules are bound by 0.05
cm and are stable for several milliseconds. The fast, all-optical method
of molecule creation via intercombination line photoassociation relies on a
near-unity Franck-Condon factor. The detection uses a weakly bound vibrational
level corresponding to a very large dimer. This is the first of two steps
needed to create Sr in the absolute ground quantum state. Lattice-trapped
Sr is of interest to frequency metrology and ultracold chemistry.Comment: 5 pages, 3 figure
Equivalent of a Thouless energy in lattice QCD Dirac spectra
Random matrix theory (RMT) is a powerful statistical tool to model spectral
fluctuations. In addition, RMT provides efficient means to separate different
scales in spectra. Recently RMT has found application in quantum chromodynamics
(QCD). In mesoscopic physics, the Thouless energy sets the universal scale for
which RMT applies. We try to identify the equivalent of a Thouless energy in
complete spectra of the QCD Dirac operator with staggered fermions and
lattice gauge fields. Comparing lattice data with RMT predictions we
find deviations which allow us to give an estimate for this scale.Comment: LATTICE99 (theor. devel.), 3 pages, 4 figure
The Limits of Creativity in Copyright: Digital Manufacturing Files and Lockout Codes
As the distinction between the digital and physical worlds continues to diminish, the necessity to reevaluate the bargain struck by the copyright regime increases in importance. Digitization brings increasingly more aspects of our world into the potential ambit of the copyright system. To understand whether and how the copyright system should apply in an increasingly digital world, it is first necessary to understand doctrinally how current copyright laws apply to new digital works. This Article corrects several errors that have appeared in the literature analyzing copyright law\u27s treatment of 3D printing and other digital manufacturing files. This Article incorporates an advanced technical understanding of digital manufacturing files and applies that understanding to copyright doctrine to clarify misunderstandings. The analysis briefly confirms that digital files created to manufacture creative objects are themselves clearly protected by copyright. On the other hand, and contrary to several assertions in the literature, most files created to manufacture purely utilitarian objects are not copyrightable because they lack a modicum of creativity. The lack of copyright protection for these files calls into question a number of assumptions, including whether they can be protected against even verbatim copying and whether open-source licenses involving these files can efficaciously bind downstream users. If digital manufacturing files of purely utilitarian objects do not enjoy copyright protection, creators may seek to embed additional, ancillary copyrightable material in the files to secure protection. This ancillary material serves as a lock-out code, which tries to prevent what would otherwise be lawful copying. This Article analyzes that phenomenon and discusses potential ways the law may react to it
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